Cross-metathesis and ring-closing metathesis of olefinic monosaccharides

Cross-metathesis reaction of α- and β-vinyl C-glycosides with alkenes

Cross-metathesis of α- and β-vinyl C-deoxyribosides and α-vinyl C-galactoside with various terminal alkenes under different conditions was studied. The cross-metathesis of the former proceeded with good yields of the corresponding products in ClCH2CH2Cl the latter required the presence of CuI in CH2Cl2 to achieve good yields of the products. A simple method for the preparation of α- and β-vinyl C-deoxyribosides was also developed. In addition, feasibility of deprotection and further transformations were briefly explored.

C-Glycosidic Genistein Conjugates and Their Antiproliferative Activity

This paper presents our attempt to investigate scopes and the limitations of olefin cross-metathesis (CM) reaction in the synthesis of complex C-glycosides of genistein and evaluation of their antiproliferative activities. Novel genistein glycoconjugates were synthesized with the utility of CM reaction initiated by first and second generation of Grubbs catalysts. The relative reactivity of utilized olefins, based on categories proposed by Grubbs, was estimated.In vitroexperiments in cancer cell lines showed that the selected derivatives (3aand3f) exhibited higher antiproliferative potential than the parent compound, genistein, and were able to block the cell cycle in the G2/M phase. The observed mechanism of action of C-glycosidic derivatives was similar to the activity of their O-glycosidic counterparts. These compounds were stable in culture medium. The obtained results show that our approach to genistein modification with application of cross-metathesis reaction allowed to obtain stable glycoconjugates with improved anticancer potential, compared to the parent isoflavone.

Observations in the Synthesis of the Core of the Antitumor Illudins via an Enyne Ring Closing Metathesis Cascade

Observations concerning the synthesis of the core spirocyclic AB-ring system of illudins using an enyne ring closing metathesis (EYRCM) cascade are discussed. Substituent effects, in addition to optimization of the reaction conditions and the olefin tether for the key EYRCM reaction, are examined.

Expeditious synthesis of enantiopure symmetrical macroheterocycles by ring-closing metathesis of ether and tether-linked 1,2-O-isopropylidenefuranosides

Bis-olefinic symmetrical carbohydrate derivatives were prepared by joining two 1,2-O-isopropylidenefuranose units either through an ether linkage or by a tether of variable size. The ring-closing metathesis (RCM) of these substrates using Grubbs' first-generation catalyst led to the synthesis of enantiopure symmetrical macroheterocycles containing nine- to twenty-five-membered rings fused to the 1,2-O-isopropylidenefuranose ring.